U.S. patent number 11,394,845 [Application Number 16/813,972] was granted by the patent office on 2022-07-19 for image forming apparatus, method of controlling the same, and storage medium.
This patent grant is currently assigned to KONICA MINOLTA, INC.. The grantee listed for this patent is KONICA MINOLTA, INC.. Invention is credited to Hisashi Uchida.
United States Patent |
11,394,845 |
Uchida |
July 19, 2022 |
Image forming apparatus, method of controlling the same, and
storage medium
Abstract
An image forming apparatus includes circuitry that binarizes
image data, a memory, and a print engine unit that forms an image
of the binarized image data. When the image data is low in
resolution, the circuitry has the image data stored in the memory
and thereafter performs on the image data, detection processing for
detecting whether or not the image data includes a predetermined
pattern before binarization processing. When the image data is high
in resolution, the circuitry binarizes the image data, thereafter
has the image data stored in the memory, thereafter further
performs multivalue converting processing on the image data, and
thereafter performs detection processing.
Inventors: |
Uchida; Hisashi (Kyoto,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
KONICA MINOLTA, INC. |
Tokyo |
N/A |
JP |
|
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Assignee: |
KONICA MINOLTA, INC. (Tokyo,
JP)
|
Family
ID: |
1000006442084 |
Appl.
No.: |
16/813,972 |
Filed: |
March 10, 2020 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20200304672 A1 |
Sep 24, 2020 |
|
Foreign Application Priority Data
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Mar 19, 2019 [JP] |
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JP2019-051501 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N
1/00872 (20130101); H04N 1/00846 (20130101); H04N
1/3871 (20130101) |
Current International
Class: |
G06F
15/00 (20060101); H04N 1/00 (20060101); H04N
1/387 (20060101) |
Field of
Search: |
;358/1.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Milia; Mark R
Attorney, Agent or Firm: Buchanan Ingersoll & Rooney
PC
Claims
What is claimed is:
1. An image forming apparatus comprising: circuitry that binarizes
image data; a memory; and a print engine unit that forms an image
of the binarized image data, wherein when the image data is low in
resolution, the circuitry has the image data stored in the memory
and thereafter performs, on the image data low in resolution,
detection processing for detecting whether the image data low in
resolution includes a predetermined pattern before binarization
processing, and when the image data is high in resolution, the
circuitry binarizes the image data high in resolution, thereafter
has the image data high in resolution stored in the memory,
thereafter further performs multivalue converting processing on the
image data high in resolution, and thereafter performs the
detection processing on the image data high in resolution for
detecting whether the image data includes the predetermined
pattern.
2. The image forming apparatus according to claim 1, wherein when
first image data is high in resolution, in the binarization
processing on the first image data, while the detection processing
on second image data is being performed, the circuitry performs the
multivalue converting processing on the first image data and
thereafter performs the detection processing, and when there is no
image data to be subjected to the detection processing, the
circuitry performs the detection processing on the first image data
before the binarization processing.
3. The image forming apparatus according to claim 1, wherein the
multivalue converting processing includes lowering resolution of
the image data.
4. The image forming apparatus according to claim 1, wherein when
the image data is low in resolution, the circuitry has the image
data stored in the memory and thereafter performs the detection
processing on the image data after edition processing and before
the binarization processing.
5. The image forming apparatus according to claim 2, wherein the
multivalue converting processing includes lowering resolution of
the image data.
6. The image forming apparatus according to claim 2, wherein when
the image data is low in resolution, the circuitry has the image
data stored in the memory and thereafter performs the detection
processing on the image data after edition processing and before
the binarization processing.
7. A method of controlling an image forming apparatus, comprising:
determining whether image data to be processed is high or low in
resolution; when the image data is low in resolution, storing the
image data low in resolution in a memory and thereafter performing
on the image data low in resolution, detection processing for
detecting whether the image data low in resolution includes a
predetermined pattern before binarization processing; when the
image data is high in resolution, binarizing the image data high in
resolution and thereafter storing the image data high in resolution
in the memory; and when the image data is high in resolution,
reading the image data high in resolution from the memory,
performing multivalue converting processing on the image data high
in resolution, and thereafter performing the detection processing
on the image data high in resolution for detecting whether the
image data includes the predetermined pattern.
8. The method according to claim 7, further comprising determining
whether the detection processing on another piece of image data is
being performed before the binarization processing, wherein when
the detection processing on another piece of image data is being
performed, the detection processing on the image data is performed
after the multivalue converting processing, and when the detection
processing on another piece of image data is not being performed,
the detection processing is performed on the image data before the
multivalue converting processing and the binarization
processing.
9. The method according to claim 7, wherein the multivalue
converting processing includes lowering resolution of the image
data.
10. The method according to claim 7, wherein when the image data is
low in resolution, the method includes storing the image data in
the memory and thereafter performing the detection processing on
the image data after edition processing and before the binarization
processing.
11. The method according to claim 8, wherein the multivalue
converting processing includes lowering resolution of the image
data.
12. The method according to claim 8, wherein when the image data is
low in resolution, the method includes storing the image data in
the memory and thereafter performing the detection processing on
the image data after edition processing and before the binarization
processing.
13. A non-transitory computer-readable storage medium having a
program stored thereon, the program, when executed by at least one
processor, causing the at least one processor to perform the method
according to claim 7.
14. A non-transitory computer-readable storage medium having a
program stored thereon, the program, when executed by at least one
processor, causing the at least one processor to perform the method
according to claim 8.
15. A non-transitory computer-readable storage medium having a
program stored thereon, the program, when executed by at least one
processor, causing the at least one processor to perform the method
according to claim 9.
16. A non-transitory computer-readable storage medium having a
program stored thereon, the program, when executed by at least one
processor, causing the at least one processor to perform the method
according to claim 10.
17. A non-transitory computer-readable storage medium having a
program stored thereon, the program, when executed by at least one
processor, causing the at least one processor to perform the method
according to claim 11.
18. A non-transitory computer-readable storage medium having a
program stored thereon, the program, when executed by at least one
processor, causing the at least one processor to perform the method
according to claim 12.
Description
The entire disclosure of Japanese Patent Application No.
2019-051501 filed on Mar. 19, 2019 is incorporated herein by
reference in its entirety.
BACKGROUND
Technological Field
The present disclosure relates to an image forming apparatus and
particularly to an image forming apparatus that performs detection
processing for detecting whether or not a predetermined pattern is
included.
Description of the Related Art
Quality of an image formed by an image forming apparatus such as a
multi-functional peripheral (MFP) has recently been improved. With
such backgrounds, significance of detection processing on image
data for printing that had conventionally been performed for
avoiding printing of a print prohibited image such as valuable
paper or banknotes has become great. For such detection processing,
for example, Japanese Laid-Open Patent Publication No. H05-014683
discloses a technique for performing detection processing after
multivalue converting processing on binary image data.
SUMMARY
When image data are uniformly subjected to binarization processing
and thereafter to multivalue converting processing and detection
processing, however, accuracy in detection may be lower.
In a conventional image forming apparatus, timing of binarization
of image data may be different depending on resolution of the image
data. For example, image data high in resolution is binarized
immediately after rasterization for minimizing an amount of data to
internally be handled, and thereafter stored in a file memory.
Image data low in resolution, on the other hand, is stored in a
file memory after rasterization without being binarized, and
thereafter read from the file memory and then binarized. When
detection processing onto image data immediately before
binarization is uniformly attempted, process delay may be caused.
More specifically, when image data high in resolution is processed
in succession to image data low in resolution, detection processing
onto preceding image data is performed after storage into and from
the file memory. Therefore, start of detection processing onto
subsequent image data is delayed, which may cause delay in output
of subsequent image data.
Dedicated circuitry for detection processing onto each of image
data high in resolution and image data low in resolution may also
be provided. In such a case, however, a circuit scale in an image
forming apparatus is larger, which may lead to significant increase
in cost for manufacturing an image forming apparatus.
Therefore, a technique for avoiding lowering in detection accuracy
in detection processing while avoiding delay in processing of image
data has been demanded.
To achieve at least one of the abovementioned objects, according to
an aspect of the present invention, an image forming apparatus
reflecting one aspect of the present invention comprises an image
processing unit that binarizes image data and an image forming unit
that forms an image of the binarized image data. The image
processing unit includes a file memory. When the image data is low
in resolution, the image data is stored in the file memory and
thereafter subjected to detection processing for detecting whether
or not the image data includes a predetermined pattern before
binarization processing. When the image data is high in resolution,
the image data is binarized, thereafter stored in the file memory,
and thereafter subjected to multivalue converting processing and
then to the detection processing.
To achieve at least one of the abovementioned objects, according to
an aspect of the present invention, a method of controlling an
image forming apparatus reflecting one aspect of the present
invention comprises determining whether image data to be processed
is high or low in resolution, when the image data is low in
resolution, storing the image data in a file memory and thereafter
performing detection processing on the image data before
binarization processing, when the image data is high in resolution,
binarizing the image data and thereafter storing the binarized
image data in the file memory, and when the image data is high in
resolution, reading the image data from the file memory, performing
multivalue converting processing on the image data, and thereafter
performing the detection processing for detecting whether or not
the image data includes a predetermined pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features provided by one or more embodiments of
the invention will become more fully understood from the detailed
description given hereinbelow and the appended drawings which are
given by way of illustration only, and thus are not intended as a
definition of the limits of the present invention.
FIG. 1 is a diagram showing an exemplary manner of use of an image
forming apparatus.
FIG. 2 is a diagram showing an exemplary hardware configuration of
an image forming apparatus 100.
FIG. 3 is a diagram showing an exemplary functional configuration
of an image processing unit 107.
FIG. 4 is a flowchart of processing in image processing unit 107
for transferring input image data to a detection processor 311.
FIG. 5 is a diagram showing an exemplary timing chart of processing
in the image processing unit in image forming apparatus 100
according to the present disclosure.
FIG. 6 is a diagram showing another exemplary timing chart of
processing in the image processing unit in image forming apparatus
100 according to the present disclosure.
FIG. 7 is a diagram showing yet another exemplary timing chart of
processing in the image processing unit in image forming apparatus
100 according to the present disclosure.
FIG. 8 is a diagram showing an exemplary timing chart of processing
in the image processing unit in an image forming apparatus
according to a comparative example.
FIG. 9 is a diagram showing an exemplary configuration of an image
processing unit 107A corresponding to the example in FIG. 8.
FIG. 10 is a flowchart of processing corresponding to the example
in FIG. 8 for transferring image data input to image processing
unit 107A to the detection processor.
DETAILED DESCRIPTION OF EMBODIMENTS
Hereinafter, one or more embodiments of the present invention will
be described with reference to the drawings. However, the scope of
the invention is not limited to the disclosed embodiments.
An embodiment of an image forming apparatus will be described below
with reference to the drawings. The same elements and components in
the description below have the same reference characters allotted
and their labels and functions are also identical. Therefore,
description thereof will not be repeated.
[Manner of Use of Image Forming Apparatus]
FIG. 1 is a diagram showing an exemplary manner of use of an image
forming apparatus. As shown in FIG. 1, an image forming system 1000
includes an image forming apparatus 100 and a user terminal 200.
Image forming apparatus 100 may be a multi-functional machine such
as an MFP or a printer. User terminal 200 may be a general-purpose
computer or a portable terminal such as a smartphone. Image forming
apparatus 100 and user terminal 200 can communicate with each other
through a network N.
[Hardware Configuration of Image Forming Apparatus]
FIG. 2 is a diagram showing an exemplary hardware configuration of
image forming apparatus 100.
Image forming apparatus 100 includes a controller 101 for overall
control of image forming apparatus 100 Image forming apparatus 100
further includes a display 102, an operation unit 103, a
communication unit 104, a storage 105, an image pick-up unit 106,
an image processing unit 107, and an image forming unit 108. These
components are connected to controller 101 through an internal
bus.
Controller 101 includes a central processing unit (CPU). Display
102 is implemented, for example, by a display apparatus such as a
liquid crystal display, an organic electro-luminescence (OEL)
display, and/or an indicator. Operation unit 103 is implemented,
for example, by an input apparatus such as a display (software key)
and/or a hardware key.
Communication unit 104 is implemented, for example, by a
communication interface such as a local area network (LAN) card.
Storage 105 is implemented, for example, by a storage apparatus
such as a hard disk drive (HDD) and/or a solid state drive (SSD).
Image pick-up unit 106 is implemented, for example, by an image
pick-up apparatus such as an image sensor.
Image processing unit 107 includes, for example, a processor (for
example, circuitry) 107X that performs processing such as
rasterization and binarization processing onto image data and a
memory 107Y that stores data representing a result of
processing.
Image forming unit 108 is implemented, for example, by a print
engine unit that includes a photoconductor that forms an
electrostatic latent image, an ink cartridge drive circuit for
supplying ink for forming an image, a roller that transports
printing paper, and a motor that drives the roller.
[Functional Configuration of Image Forming Apparatus]
FIG. 3 is a diagram showing an exemplary functional configuration
of image processing unit 107. Image processing unit 107 includes a
raster image processing (RIP) unit 301, an RIP buffer memory 302, a
direct memory access (DMA) controller 303, a binarization processor
304, a compression and decompression processor 305, a file memory
306, an image editor 307, a binarization processor 308, a print
controller 309, a multivalue converting processor 310, and a
detection processor 311.
RIP unit 301, DMA controller 303, binarization processor 304,
compression and decompression processor 305, image editor 307,
binarization processor 308, print controller 309, multivalue
converting processor 310, and detection processor 311 are each
implemented by at least one processor. Each of them is implemented
by execution of a given program by a general-purpose processor
and/or a dedicated processor (for example, hardware such as an
ASIC). RIP buffer memory 302 and file memory 306 are each
implemented by a memory.
RIP unit 301 rasterizes input image data and has the rasterized
image data stored in RIP buffer memory 302.
DMA controller 303 transfers image data stored in RIP buffer memory
302 to each element in image processing unit 107. More
specifically, DMA controller 303 transfers image data categorized
as image data high in resolution to binarization processor 304 and
transfers image data categorized as image data low in resolution to
compression and decompression processor 305. By way of example, DMA
controller 303 categorizes image data having resolution not larger
than a given threshold value as image data low in resolution and
categorizes image data having resolution exceeding the threshold
value as image data high in resolution. An exemplary threshold
value is set to 600 dots per inch (dpi).
By way of example, image data of 600 dpi and image data of 1200 dpi
may be input to image forming apparatus 100. In this case, image
data of 600 dpi is handled as image data low in resolution and
image data of 1200 dpi is handled as image data high in
resolution.
Binarization processor 304 binarizes image data. DMA controller 303
transfers image data binarized by binarization processor 304 to
compression and decompression processor 305.
Compression and decompression processor 305 compresses image data.
DMA controller 303 transfers compressed image data to file memory
306.
DMA controller 303 transfers image data input as image data high in
resolution among image data stored in file memory 306 to multivalue
converting processor 310 as necessary, after decompression by
compression and decompression processor 305. DMA controller 303
transfers image data input as image data low in resolution among
image data stored in file memory 306 to image editor 307 after
decompression by compression and decompression processor 305.
Image editor 307 performs edition processing on image data.
Enlargement processing represents one example of edition processing
and reduction processing represents another example. DMA controller
303 transfers image data edited by image editor 307 to binarization
processor 308 and detection processor 311.
Binarization processor 308 binarizes image data.
Multivalue converting processor 310 performs multivalue converting
processing on image data. Multivalue converting processor 310 may
perform multivalue converting processing on image data so as to
lower resolution thereof to be lower than resolution at the time of
input of the image data. For example, image data at resolution of
1200 dpi input to image processing unit 107 is binarized and
thereafter converted to multi-valued data at resolution of 600
dpi.
When image data input to image processing unit 107 is high in
resolution, DMA controller 303 transfers the image data read from
RIP buffer memory 302 or the image data processed by multivalue
converting processor 310 to detection processor 311 in accordance
with a condition which will be described later with reference to
FIG. 4.
Detection processor 311 performs detection processing for detecting
a specific image pattern in the image data. Examples of the
specific image pattern include a pattern that constitutes an image
of which output is prohibited, such as an image of banknotes.
Detection processor 311 outputs a result of detection processing to
DMA controller 303.
On condition that the image data has been determined as not
including the specific image pattern in detection processing, DMA
controller 303 transfers image data high in resolution decompressed
by compression and decompression processor 305 or image data low in
resolution binarized by binarization processor 308 to print
controller 309.
When the image data has been determined as including the specific
image pattern in detection processing, DMA controller 303 does not
transfer the image data to print controller 309. Formation of an
image in accordance with image data that may include the specific
image pattern in image forming apparatus 100 is thus avoided. In
this case, DMA controller 303 may notify controller 101 of a result
of detection processing onto the image data. In response,
controller 101 may have display 102 show information indicating
that the image data (may) contains an image of which printing is
prohibited.
Print controller 309 transfers the image data to image forming unit
108 and controls image forming unit 108 to form an image in
accordance with the image data on a recording medium such as
printing paper.
[Flow of Processing]
FIG. 4 is a flowchart of processing in image processing unit 107
for transferring input image data to detection processor 311. The
processing is performed by a hardware element implementing DMA
controller 303 and performed by execution of a given program by a
given hardware element (circuitry) by way of example.
The processing in FIG. 4 is started, for example, in response to
input of an instruction to execute a print job from user terminal
200 to image forming apparatus 100. The processing in FIG. 4 should
only be started in response to an instruction to execute a job
including formation of an image, and may be started in response to
an instruction to execute a copy job (for example, pressing of a
copy button) in image forming apparatus 100.
In step S10, DMA controller 303 determines whether or not RIP
(rasterization by RIP unit 301) of image data input to image
processing unit 107 has been completed. When DMA controller 303
determines that RIP has not yet been completed, the process stays
in step S10 (NO in step S10), and when it determines that RIP has
been completed, the DMA controller allows control to proceed to
step S20 (YES in step S10).
In step S20, DMA controller 303 determines whether or not image
data in a job from which an image is formed is high in resolution.
In one example, when a file of which printing is indicated in a job
includes an image high in resolution, DMA controller 303 determines
the image data as being high in resolution (for example, resolution
exceeding 600 dpi) and determines the image data as being in high
in resolution. In another example, when the image data does not
include an image high in resolution, DMA controller 303 determines
the image data as not being high in resolution. When DMA controller
303 determines the image data as being high in resolution, the DMA
controller allows control to proceed to step S40 (YES in step S20),
and otherwise, the DMA controller allows control to proceed to step
S30 (NO in step S20).
In step S30, DMA controller 303 transfers image data edited by
image editor 307 and yet to be binarized by binarization processor
308 to detection processor 311 and quits the process in FIG. 4.
In step S40, DMA controller 303 determines whether or not detection
processing is busy. In one example, the detection processing being
busy means that image data in another job is being processed by
detection processor 311. The detection processing not being busy
means that image data is not being processed by detection processor
311. When DMA controller 303 determines that the detection
processing is busy, the DMA controller allows control to proceed to
step S60 (YES in step S40), and when it determines that the
detection processing is not busy, the DMA controller allows control
to proceed to step S50 (NO in step S40).
In step S50, DMA controller 303 transfers image data binarized by
binarization processor 304 and thereafter subjected to multivalue
converting processing in multivalue converting processor 310 to
detection processor 311 and quits the process in FIG. 4.
In step S60, DMA controller 303 transfers image data yet to be
binarized by binarization processor 304 (the image data read from
RIP buffer memory 302) to detection processor 311 and quits the
process in FIG. 4.
[Timing Chart]
FIGS. 5 to 8 each show an exemplary timing chart of processing in
the image processing unit in image forming apparatus 100 according
to the present disclosure or an image forming apparatus in a
comparative example. Each of FIGS. 5 to 8 shows a timing chart in
execution of two successive print jobs (a "job 1" and a "job 2" in
each figure). In each example shown in FIGS. 5 to 8, each of "job
1" and "job 2" represents a job for a file including image data of
three pages.
Each of FIGS. 5 to 8 shows processing performed onto image data,
such as "RIP". More specifically, RIP (rasterization) A1 by RIP
unit 301, compression processing A2 and decompression processing A3
by compression and decompression processor 305, image edition A4 by
image editor 307, binarization processing A5 by binarization
processor 308, detection processing X by detection processor 311,
and print processing Y by print controller 309 are shown as
processing performed onto image data low in resolution.
RIP (rasterization) B1 by RIP unit 301, binarization processing B2
by binarization processor 304, compression processing B3 and
decompression processing B4 by compression and decompression
processor 305, detection processing X by detection processor 311,
and print processing Y by print controller 309 are shown as
processing performed onto image data high in resolution. FIG. 7
further shows multivalue converting processing B5 by multivalue
converting processor 310.
In each of FIGS. 5 to 8, the abscissa represents lapse of time.
FIGS. 5 to 8 show on which page in which job image data is
subjected to each type of processing. Each of FIGS. 5 to 8 will be
described below.
(FIG. 5: Example in Which Jobs Low in Resolution Are Successively
Executed)
In an example in FIG. 5, each of job 1 and job 2 is a print job for
printing image data low in resolution. As shown in FIG. 5,
initially, image data on a first page in job 1 is subjected to RIP
A1. When RIP on the image data on the first page in job 1 is
completed, image data on the first page is transferred to
compression and decompression processor 305 and RIP A1 on image
data on a second page is performed. Image data on each of the first
page to a third page in job 1 is sequentially processed in RIP A1,
compression processing A2, decompression processing A3, image
edition A4, and binarization processing A5. Each piece of image
data is processed in detection processing X in parallel to
processing in binarization processing A5. As detection processing X
for each page is completed, print processing Y onto that page is
performed on condition that the specific image pattern described
above was not detected in the detection processing.
In the example in FIG. 5, after RIP A1 onto the last page (the
third page) in job 1, RIP A1 onto a top page (a first page) in job
2 is started. For job 2 as well, image data on each of the first
page to the third page is sequentially processed in RIP A1,
compression processing A2, decompression processing A3, image
edition A4, and binarization processing A5.
In the example in FIG. 5, image edition A4 of the first page in job
2 ends at time t12. Detection processing X onto the third page in
job 1 ends at time t11 before time t12. In other words, detection
processing X onto the top page in job 2 can be started without
waiting for the end of detection processing X onto the last page in
job 1. Thus, in processing of the image data in job 2, delay which
may be caused by waiting for processing onto the image data in job
1 is avoided.
(FIG. 6: Example (1) in Which Job High in Resolution Is Executed
After Job Low in Resolution)
In an example in FIG. 6, job 1 is a print job for printing image
data low in resolution and job 2 is a print job for printing image
data high in resolution.
In the example in FIG. 6 as well, as in the example in FIG. 5,
image data on each of the first page to the third page in job 1 is
sequentially processed in RIP A1, compression processing A2,
decompression processing A3, image edition A4, and binarization
processing A5. Each piece of image data is processed in detection
processing X in parallel to processing in binarization processing
A5. When detection processing X onto each page is completed, print
processing Y onto that page is performed on condition that the
specific image pattern described above was not detected in the
detection processing.
In the example in FIG. 6, RIP B1 onto a first page in job 2 is
started at the timing of end of the print processing onto the first
page in job 1. Thereafter, image data on each of the first page to
the third page also in job 2 is sequentially processed in RIP B1,
binarization processing B2, compression processing B3, and
decompression processing B4.
In the example in FIG. 6, at time t22, RIP B1 onto the first page
in job 2 ends and binarization processing B2 is started. Detection
processing X onto the last page in job 1 ended at time t21 before
time t22. In other words, image processing unit 107 (DMA controller
303) can determine that detection processing X is not busy at the
time when it attempts binarization processing B2 onto the first
page in job 2 (NO in step S40 in FIG. 4). Therefore, in the example
in FIG. 6, image data before binarization processing B2 is
processed in detection processing X.
In the example in FIG. 6, detection processing onto image data in
job 2 is performed without waiting for end of detection processing
onto the image data in job 1 and image data before binarization
processing B2 (which remains high in resolution) can be
processed.
(FIG. 7: Example (2) in Which Job High in Resolution Is Executed
After Job Low in Resolution)
In an example in FIG. 7, as in the example in FIG. 6, job 1 is a
print job for printing image data low in resolution and job 2 is a
print job for printing image data high in resolution.
In the example in FIG. 7 as well, as in the example in FIG. 6,
image data on each of the first page to the third page in job 1 is
sequentially processed in RIP A1, compression processing A2,
decompression processing A3, image edition A4, and binarization
processing A5. Each piece of image data is processed in detection
processing X in parallel to processing in binarization processing
A5. When detection processing X onto each page is completed, print
processing Y onto that page is performed on condition that the
specific image pattern described above was not detected in the
detection processing.
In the example in FIG. 7, RIP B1 onto image data on the first page
in job 2 is started in a relatively early stage after the end of
RIP A1 onto the last page (the third page) in job 1. Therefore, for
image data on the first page in job 2, at the timing (time t31) of
completion of RIP B1 and start of binarization processing B2,
detection processing X onto image data on the last page in job 1
has not yet ended. Detection processing X onto the image data on
the last page in job 1 ends at time t32 after time t31. In other
words, at time t31, detection processing X is determined as being
busy (YES in step S40).
Then, in the example in FIG. 7, image processing unit 107 (DMA
controller 303) performs detection processing X onto image data in
job B2 that has been subjected to binarization processing B2,
compression processing B3, decompression processing B4, and
multivalue converting processing B5, as described as control in
step S60. Detection processing X onto the image data on the first
page in job 2 is thus started at time t33 after time t32.
In the example in FIG. 7, image processing unit 107 performs
detection processing onto image data low in resolution before it is
binarized. Lowering in accuracy in detection processing can thus be
avoided Image processing unit 107 performs detection processing
onto image data high in resolution after it is subjected to
multivalue converting processing even though it has been binarized.
Thus, in a scene where a job (image data) high in resolution is
executed after a job (image data) low in resolution, delay in start
of detection processing for the job high in resolution that may be
caused by waiting for detection processing for the job low in
resolution can be avoided. In such a scene, delay in processing can
be avoided while lowering in accuracy in detection processing is
avoided.
(FIG. 8: Example (3) in Which Job High in Resolution Is Executed
After Job Low in Resolution)
In an example in FIG. 8, as in the example in FIG. 7, job 1 is a
print job for printing image data low in resolution and job 2 is a
print job for printing image data high in resolution. The example
in FIG. 8 is a comparative example with respect to the example in
FIG. 7 and does not include multivalue converting processing B5.
The comparative example shown in FIG. 8 will be described in
further detail with reference to FIGS. 9 and 10.
FIG. 9 is a diagram showing an exemplary configuration of an image
processing unit 107A corresponding to the example in FIG. 8. FIG.
10 is a flowchart of processing corresponding to the example in
FIG. 8 for transferring image data input to image processing unit
107A to the detection processor. The configuration in FIG. 9 does
not include multivalue converting processor 310 as compared with
the configuration in FIG. 3. In the example in FIG. 9, when image
data is high in resolution, DMA controller 303 transfers image data
before binarization processing to detection processor 311. When
detection processor 311 is performing detection processing onto
another piece of image data, DMA controller 303 transfers next
image data to detection processor 311 after end of detection
processing onto that image data.
In processing in FIG. 10, as compared with the processing in FIG.
4, when DMA controller 303 determines that the detection processing
is busy (YES in step S40), it has control stay in step S40 until
the detection processing is no longer busy. DMA controller 303
transfers image data to detection processor 311 on condition that
it determines that the detection processing is not busy (NO in step
S40).
Referring back to FIG. 8, even when RIP B1 onto image data in job 2
ends at time t31, image data in job 1 is being processed in
detection processing X. Therefore, DMA controller 303 is unable to
transfer image data on the first page in job 2 from RIP buffer
memory 302 to detection processor 311. Since image data on the
first page is stored in RIP buffer memory 302, RIP unit 301 is
unable to start RIP onto image data on the second page in job
2.
At time t32, DMA controller 303 starts transfer of image data on
the first page in job 2 to detection processor 311. DMA controller
303 thus starts RIP onto image data on the second page in job 2 at
time t32. Since the example in FIG. 8 does not include multivalue
converting processing B5, there is no path through which image data
proceeds to binarization processing B2, compression processing B3,
and decompression processing B4 after RIP B1. Thus, start of RIP
onto image data on the second page in job 2 is significantly
delayed as compared with the example in FIG. 7 and hence start of
processing onto image data on the second page in binarization
processing B2 or later is also delayed. Thus, even when detection
processing X onto each page in job 2 ends early, end of
decompression processing B4 is later than in the example in FIG. 7
and consequently start of print processing Y is delayed (time
t41).
In other words, in the example in FIG. 7, with progress of
detection processing X onto image data in job 1 before job 2, DMA
controller 303 can select whether image data before binarization
processing B2 or image data after binarization processing B2 and
after multivalue converting processing B5 should be subjected to
detection processing X. Thus, image forming apparatus 100 can avoid
lowering in accuracy in detection processing and delay in
processing as much as possible.
Although embodiments of the present invention have been described
and illustrated in detail, the disclosed embodiments are made for
purposes of illustration and example only and not limitation. The
scope of the present invention should be interpreted by terms of
the appended claims
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